Background and methods: The expression of p53 protein in 100 large bowel cancers was studied immunohistochemically by use of a monoclonal antibody (PAb1801).
Results: Immunoreactivity was found in 61.0% of specimens from 100 patients with colorectal cancer. The pattern of p53 expression was mainly detected in the nuclei of the cancer cells. There was no significant correlation between the expression of p53 and the histologic grade, tumor size, serosal invasion, lymphatic invasion, venous invasion, lymph node metastasis, or liver metastasis. However, patients with p53-positive tumors had a greater relative risk of death compared with those with p53-negative tumors. The p53 negative-tumors showed a recurrence rate of 5.9%; for the p53 positive-tumors, a recurrence rate of 23.8% was recorded. The 3-year survival rate was 96.7% of 39 patients with p53-negative carcinomas and 61.8% for the patients with p53-positive tumors; there was a significant difference in the rate between the two groups of patients (P < 0.05). The growth fraction of p53-positive tumors determined with a monoclonal antibody against DNA polymerase alpha (49.0%) was significantly higher than that of p53-negative tumors (40.7%, P < 0.01).
Conclusions: These results suggest that the immunoreactivity of p53 may be a biologic marker of prognostic significance.